ESBO manufactured from soybean oil through the process of epoxidation. Polyunsaturated vegetable oils are widely used as precursors to epoxidized oil products because they have high numbers of carbon-carbon double bonds available for epoxidation.
The epoxide group is more reactive than double bond, thus providing a more energetically favorable site for reaction and making the oil a good hydrochloric acid scavenger and plasticizer.
Food products that are stored in glass jars are usually sealed with gaskets made from PVC. ESBO is one of the additives in the PVC gasket.
It serves as a plasticizer and a scavenger for hydrochloric acid released when the PVC degrades thermally, e.g. when the gasket is applied to the lid and food product undergoes sterilization. ESBO is also used in PVC cling films for wrapping foods and toys.